Showing papers on "X-ray lithography published in 2020"

Misalignment measurement with dual-frequency moiré fringe in nanoimprint lithography.

Abstract: We explore an easy-to-implement moire-based measurement scheme for the mask-wafer misalignment in nanoimprint lithography. By introducing the beat signal of moire fringes, the measurement range increase by dozens or even hundreds of times, while the measurement accuracy doesn’t get affected and still kept in nanoscale. Moreover, the alignment signal, collected throughout the whole imprint process, is independent of the wafer-mask gap and beam fluctuation, which makes it very suitable for the misalignment measurement in NIL. The experiment shows that sub-10 nm alignment could be obtained within a measurement range of 500µm, which is expected to be improved after the parameter optimization.

Challenges in fabrication of high aspect ratio electrostatic comb-drive microactuator using one-step X-ray lithography

Abstract: A High Aspect Ratio (HAR) electrostatic comb-drive microactuator of polymethyl-methacrylate (PMMA) is designed to deliver nearly 40 µm uniaxial displacement at 25 V DC. The HAR comb-drive microstructures are fabricated via one-step X-ray lithography (OXL). Polyimide-Au X-ray mask is fabricated and used to pattern 200 μm, 500 μm and 800 μm thick PMMA by deep X-ray lithography (DXRL), followed by drying/release and selective metallization for the development of HAR electrostatic microactuator. The release was optimized with the help of various low-surface-tension liquids. 200 μm and 500 μm thick microstructures were successfully released whereas, 800 μm structures could not be released due to the higher depth and associated capillary force. In addition, non-uniform distribution of Au on the side walls of overlapped region of comb fingers, during metallization, resulted in uneven distribution of electrostatic force followed by short-circuiting of HAR (i.e. 40) microactuator. These are the potential issues in the fabrication of HAR microstructures and devices by OXL and discussed in details in this paper.

Microfabrication of Ni-Fe Mold Insert via Hard X-ray Lithography and Electroforming Process

Abstract: In this research, a Ni-Fe mold insert for the efficient replication of high aspect-ratio microstructure arrays was fabricated via hard X-ray lithography and an electroforming process. For the X-ray exposure on a photoresist, a gold-based X-ray mask was prepared with conventional UV photolithography. The gold thickness was designed to be over 15 μm to prevent development underneath the absorber and to enhance the adhesion strength between the photoresist and substrate. By using the X-ray mask, a positive-type photoresist was selectively exposed to X-ray under an exposure energy of 4 kJ/cm3. Thereafter, the exposed region was developed in a downward direction to effectively remove the residual photoresist from the substrate. During the evaporation process, deionized water mixed with a surface additive prevented the bending and clustering of the photoresist microstructure arrays by lowering the capillary force, resulting in a defect-free mother structure for electroforming. Lastly, the mother structure was uniformly Ni-Fe electroformed on a conductive substrate without the formation of any pores or detachment from the substrate. Based on the proposed microfabrication process, a Ni-Fe mold insert with a 183 μm pattern size, 68 μm gap size, 550 μm height, 2116 microcavities and a hardness of 585 Hv was precisely manufactured. It can be utilized for the mass production of high aspect ratio metal and ceramic microstructure arrays in micro molding technologies.

Self-aligned single-exposure deep x-ray lithography

Abstract: The method of deep X-ray lithography has been developed, which allows the formation of self-aligned microstructures. Examples of microstructures are presented.

Method of manufacturing self-bearing x-ray lithography mask

Abstract: FIELD: medicine.SUBSTANCE: invention relates to a method for producing X-ray lithography mask. X-ray mask manufacturing method includes processes of formation of topological masking X-ray absorbing layer by perforation of metal foil and its fixation in support ring. On one of the surfaces of the metal foil a protective mask is made of metal having a low etching rate compared to the foil metal in the corresponding chemically active plasma etching foil metal, then foil is placed on cooled table of plasma chemical etching and through holes are etched in foil through protective mask by action of flow of chemically active ions.EFFECT: as result, X-ray lithography mask produced in this manner does not contain a bearing membrane and therefore is characterized by maximum achievable levels of X-ray lithographic contrast (with given material and thickness of masking layer), as well as relatively high mechanical strength.5 cl, 5 dwg